"The question all but asks itself: Why is anybody still writing plays? Theater, after all, is no longer a central part of the American cultural conversation, the way it was when Arthur Miller and Tennessee Williams walked the earth. Nowadays most educated people would just as soon stay home and watch "Breaking Bad" as shell out a hundred bucks to see a Broadway play—assuming that there are any plays on Broadway worth seeing, which long ago ceased to be a safe bet.
Honestly, I do like that I've met nice people, but as a playwright, that is not why I write plays. I also don't write plays because I really like sitting in the room and hearing the reactions (a luxury, apparently, that TV writers don't get?) I don't do it for applause, or to satisfy myself or feel the love of others. Frankly, the theater I like is usually a bit terrifying and difficult: the sort that makes people leave feeling unsettled, and not like they love you.
I write plays because they are the long-standing, traditional form of art that I've chosen for my medium. Does there need to be further explanation than that? Just because photographs exist, does that mean painters need to explain why they still paint? I do not concede that drama is no longer a part of the cultural conversation. Tony Kushner may not make thousands of dollars from Angels in America...but it's still Angels in America. It's value is immeasurable; it's a permanent part of the American canon. That's work of a value that is expressly disproportional to the amount that he is paid for it. He gets paid less than a baseball player. Fine. So do schoolteachers. Does anyone ask why teachers bother?
Should poets stop writing poetry just because none of them is Robert Frost? Because the culture has changed? Are poets, in fact, just writing poems because poems are fun to write? No. They are important, and valuable, and necessary. Even the ones you've never heard of. Even the ones you've never read.
Theater is like any art. I honestly am amazed when people ask why it's made.